The present invention relates to a method for producing a threaded nut of a screw drive, in particular of a ball screw. Ball screws convert rotational movements into translatory movements.
DE 19944876 A1, for example, discloses an actuating device for a parking brake of a motor vehicle, in which actuating device a ball screw is provided.
The threaded spindle, which is driven by an electric motor, effects a relative axial displacement between the threaded nut and the threaded spindle, wherein the threaded nut, in its feed direction, exerts a pressure force on a friction pad of a disk brake via further machine parts. To release the parking brake, the threaded spindle is driven in the opposite rotational direction; the threaded nut travels back on the threaded spindle until it reaches a stop position in which a stop takes effect. The circumferential stop takes effect before the threaded nut can be axially braced with a stop part which is arranged on the threaded spindle and which has the projection.
In the ball screw application described here, a circumferential stop of said type is important for correct functioning of the ball screw. Without a circumferential stop of said type, it would undesirably be possible for the threaded nut to be axially braced in the manner of a tightened screw nut, and a release of said axial bracing action would be possible only by imparting a considerable torque.
In said known ball screw, the projections provided on the threaded nut and on the stop part must be coordinated with one another: before the final possible rotation between the threaded nut and the stop part, there must still be an axial spacing between the two projections sufficient to prevent these from abutting against one another at the end side. During the final rotation, the two projections overlap one another in the axial direction; the two projections finally circumferentially abut against one another, and a further relative rotation between the threaded spindle and the threaded nut is prevented.
The projection which is formed on the end side of the threaded nut is of solid form in order to be able to accommodate even large torques during the abutment of the threaded nut. To produce said projection provided on the end side, it is expedient for the ball nut to be produced in a cutting process.
DE 102007046180 discloses a similar actuating device. Here, too, a circumferential stop for the threaded nut is provided, which stop is formed as a stop surface formed on the inner circumference of the threaded nut. Said stop surface is formed on a pin which is fastened to the threaded nut.